François-Joseph Servois (1767-1847) was a priest, artillery officer, and professor of mathematics. His research spanned many areas, including geometry and the foundations of calculus. In this article, we introduce readers to a perpetual calendar created by Servois (see Figure 1), provide an annotated translation of Servois' 1813 “Calendrier perpétuel" [1813], and suggest some possible uses for it in the classroom.

Figure 1. Servois' perpetual calendar appeared on page 92 of his 1813 article, “Calendrier perpétuel." The signature in the lower right corner is that of Joseph Diaz Gergonne, the editor of the journal, Annales des mathématiques pures et appliquées (also known as "Gergonne's journal"), in which the article appeared. (Image used courtesy of the Science, Industry and Business Library of the New York Public Library.)

Before we explore Servois' perpetual calendar further, we provide a brief review of the history of calendars.